Propeller pencil



sept. 3o 1924.

' 1,510,079 G. R. HUDSON IROPELLER PENC IL Filed Feb. 2, 1922 ill ,wwwa/W7@ Patented Sept. 30, 1924.

UNITE-D STATES vPATENT. OFFICE.

PROPELLER PENCIL.

.Application filed February 2, 1922. Seri-a1 No. 533,616.

T 0 all whom it may concern.'

Be it known that l, Gnonon ltneiNAnn HUnsoN, of 612, Bank Chambers, High Holborn, London, W.. C. l. England, a subject of the Kin-g of Great Britain and Ireland, have invented certain new and useful Improvements in or Relating to Propeller Penn cils, of which the lfollowing is a specification.

This invention relates to propeller pencils of the type in which the lead is held in a carrier provided with a key adapted to travel in a slot in a tubular member in which the carrier moves, the key being provided with a notch adapted to engage a wire coil wound in the form of helix around the tubular member.

In pencils of this type as hitherto constructed the helical member enclosed in and soldered to a. holder or coil box and the tubular member is placed in and secured to a casing so that when rotating the holder with respect to the casing', the helical member is rotated causingthe carrier to move along inside the slotted tubular member.

In such known pencils damage may be caused to the mechanism by overwinding and causing the spring or coil to become detached from ,the holder or coil box, and further there is generally a little back lash or movement between the holder and the slotted tubular member.

The object of this invention is to overcome these defects.

ln a pencil made in accordance with this invention the helical member is in frictional contact with the holder or coil box and is formed or bent to provide a stop to engage the key at the end of its forward or backward movement so that in use should an attempt be made to overwind the pencil there is no soldered joint which can come undone, but the holder or coil box merely slips on the spring without any undue turning pressure. In order to take up back lash a compression spring is inserted between a flange on the holder or coil box and a flange on the slotted tubular member.

In the drawings filed herewith Fig'. 1 is a partly sectional view of one form of pencil made in accordance with this invention in which the wire helix is shown in full;

Fig. 2 is an elevation of the lead carrier;

Fig. 3 is an end view of the carrier;

Fig. 4 is a sectional elevation of a modified form of pen-cil made in accordance with this invention.

Fig. is a fragmentary sectional view illustrating a further modification.

Referring to the drawings: y

a is the carrier provided with a key b in which al notch b is provided and c is the lead. The carrier is 'adapted to travel in a tubular member (Z, the key Y) passing along the slot c formed in the member (l and shown in the drawings in dot and dash lines. Round the tubular member l a wire f is wound in the form of a helix the wire engaging the notch in the key The ends of the wire are bent at g and 71, so as to lie parallel to the longitudinal axis of the pencil and form a stop to engage the key 7 when the carrier is at either end of its movement. Over the helical member y is a holderI y', provided with an internal collar or flange 7c. The end of the holder is provided with a chamber m and cap n to hold the spare leads as is common with propeller pencils. The open end of the tu lbular member (Z is provided with a casing or front part o fixed to it.

In Fig. l theI end of the tubular member d is shown expanded over a washer placed against the flange c.

In use to propel the lead the holder is rotated with respect to the tube CZ and casing 0. The helical member f is carried round with the holder by frictional engagement therewith and the key ZJ engages the helical member causing the carrier a to travel in the tubular member Z until the carrier comes to the end of its movement when the key 7) engages the end g or the end t of the helical member. Should an at-y tempt be made to overwind the pencil the holder slips on the helical member and no damage is done to the moving parts.

In Fig. 4l the back part of' the flange 7e is cut away to allow a small compression spring p to be inserted between the said flange 75 and the washer g as shown. This modification does not make any appreciable difference in the strength of the flange 7c which still retains a considerable thickness.

The effect of the. compression spring p inserted in the manner indicated is to hold the casing or front part 0` of the tubular member CZ firmly against the front end of the holder j, to take up wear, and to compensate for any other causes tending to produce backlash between the two parts referred to.

In the form of pencil illustrated in Fig. 5 the inside of the holder j is provided with a brass tubular lining r which has* at the front end a flared or enlarged conical portion s which is adapted to engage a groove t in the holder Near the other end of the lining rand in a position corresponding `to that of the flange in the pencilholders hereinbefore described, is an internal ridge u, While a brass bushing o having a peripheral groove corresponding to the ridge u is adapted to be secured in the tubular lining` r to take the place of the flange 7c in the pencil-holders already described* Thus the components y', r, and #2.: form a compound integral structure constituting the holder proper denoted by the letter y' in the other examples. The tubular member CZ passes' through a hole in the bushing o and is flared and provided with a 'washer g and preferably, a compression spring p as already described. This form is particularly efiicient in that, owing to the manner in which the holder y', tubular lining r and brass bushing u are secured together, it is impossible to pull the pencilholder to pieces as in the case of so many propelling pencil-holders now constructed; and the provision of the brass lining r pre- Vents the holder from warping when of a material liable to warp and rendering the pencil-holder useless.

What I claim and desire to secure by Letters Patent is l. In a pencil, the combination with a rotatable holder, of a rotatable helix within the holder for extruding and withdrawing the movable pencil point, the turns of said helix being expanded into frictional engagement with the interior of the holder rotation of the adapted to slip further rotation so as to rotate with the holder, said holder being upon the helix in case the of the helix is obstructed.

2. In a propeller' pencil, the combination with a carrier ior the. lead, of a tubular member surrounding the. carrier, a slot in the said member, a key on the carrier projecting into the slot, an opening in the key, a wire helix surrtmnding the tubular member engaging in the said opening, the ends of the helix being bent into a position parallel to the longitudinal axis ol the pencil to form stops to engage the said key at each end of the movement ol the carrier. a holder enclosing the tubular member and making it'iit-.tional engagement with the helix` and means for retaining the tubular member stationary while rotating the holder and helixv to extrude and \\'ithdra'\v the lead as desired.

3. In a propeller pencil, in combination, a carrier il`or the lead, ay tubular member surrounding the farrier, a slot in the said member, a key on the carrier lnojeeting into the slot, an opening in the key. a wire helix surrounding the tubular member eugaging in the said opening, a casing h'Xed to the front part oit the tubular member, a holder making lirictional engagement; with the helix enclosing the tubular member and abutting against the said easing.l an internal shoulder near the rear end of the holder, a collar on the rear end of the tubular member, and a compression spring inserted between the said shoulder and the washer to maintain the rubbing contact between the front end of the holder and the casing fixed to the tubular member.

In testimony whereof I have signed my naine to this specification.

GEORGE REGINALD HUDSON. 

